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Preparation process of glycine

A preparation process, glycine technology, applied in the chemical industry, can solve the problems of prolonged concentration time, long reaction time, and high production cost, and achieve the effects of reducing raw material decomposition, reducing retention time, and improving production capacity

Inactive Publication Date: 2012-05-02
CHONGQING UNISPLENDOUR CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above-mentioned preparation process has mild reaction conditions, easy control, and simple post-treatment, but it has the following problems: the reaction time in step 1) is long (≥0.5 hours), which easily leads to decomposition of raw materials, pyrolysis polymerization of aminoacetonitrile and formation of by-products; The concentration of inorganic alkali sodium hydroxide solution in step 2) is low (32%), the alkaline hydrolysis temperature is low (40~60°C), and the alkaline hydrolysis rate is slow, which will easily lead to the formation of colored impurities, thereby increasing the difficulty of decolorization and decolorization agent In addition, the volume of the alkaline hydrolysis solution is large, which also prolongs the subsequent concentration time and increases energy consumption; step 4) does not disclose the recycling method of the mother liquor, the waste mother liquor has a large amount of treatment, the product yield is low, and the production cost is high. high

Method used

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  • Preparation process of glycine
  • Preparation process of glycine

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Experimental program
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Effect test

Embodiment 1

[0027] The first batch of production specifically includes the following steps:

[0028] a. Ammonification: Mix 228.06 g of hydroxyacetonitrile and 1175 g of ammonia water with a concentration of 23% by mass (the molar ratio of hydroxyacetonitrile to ammonia is 1:4), and pump it into a tubular reactor at a temperature of 83°C and a pressure of Under the condition of 1.3MPa, the ammoniation reaction was carried out, and the reaction time was adjusted to be 6 minutes by controlling the flow rate to obtain the aminoacetonitrile reaction solution;

[0029] b. Alkaline hydrolysis: Add 351.82 g of sodium hydroxide solution with a mass percent concentration of 50% in advance in the alkaline hydrolysis reactor (the molar ratio of sodium hydroxide to hydroxyacetonitrile is 1.1:1), and use the alkaline hydrolysis reactor in the tubular reaction The aminoacetonitrile reaction liquid is collected at the outlet of the reactor, and the aminoacetonitrile reaction liquid that enters the alk...

Embodiment 2

[0040] The first batch of production specifically includes the following steps:

[0041] a. Ammonification: Mix 228.06g of hydroxyacetonitrile and 881.3g of ammonia water with a concentration of 23% by mass (the molar ratio of hydroxyacetonitrile to ammonia is 1:3), pump it into the tubular reactor, and heat it at a temperature of 50°C and a pressure of Under the condition of 2.0MPa, the ammoniation reaction was carried out, and the reaction time was adjusted to be 4 minutes by controlling the flow rate to obtain the aminoacetonitrile reaction solution;

[0042] b. Alkaline hydrolysis: add 416g of sodium hydroxide solution with a concentration of 50% by mass in advance in the alkaline hydrolysis reactor (the molar ratio of sodium hydroxide to hydroxyacetonitrile is 1.3:1), and use the alkaline hydrolysis reactor in the tubular reactor The outlet of the aminoacetonitrile reaction liquid is collected, and the aminoacetonitrile reaction liquid entering the alkali hydrolysis rea...

Embodiment 3

[0053] The first batch of production specifically includes the following steps:

[0054] a. Ammonification: Mix 228.06g of hydroxyacetonitrile and 1762.5g of ammonia water with a concentration of 23% by mass (the molar ratio of hydroxyacetonitrile to ammonia is 1:6), pump it into the tubular reactor, and heat it at a temperature of 100°C and a pressure of Under the condition of 0.5MPa, the ammoniation reaction was carried out, and the reaction time was adjusted to be 10 minutes by controlling the flow rate to obtain the aminoacetonitrile reaction solution;

[0055] b. Alkaline hydrolysis: Add 384g of sodium hydroxide solution with a mass percentage concentration of 50% in advance in the alkaline hydrolysis reactor (the molar ratio of sodium hydroxide to hydroxyacetonitrile is 1.2:1), and use the alkaline hydrolysis reactor in the tubular reactor The outlet of the aminoacetonitrile reaction liquid is collected, and the aminoacetonitrile reaction liquid that enters the alkali ...

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Abstract

The invention discloses a preparation process of glycine, which comprises amination, alkaline hydrolysis, ammonia discharge acidification, decolorizing, concentration, desalting, crystallization and recrystallization steps, wherein in the amination step, hydroxyacetonitrile and ammonia water are mixed in a tubular reactor, and a reaction is undergone at the temperature of 50-100 DEG C under the pressure of 0.5-2.0 MPa for 4-10 minutes; and in the alkaline hydrolysis step, 30-50 percent of sodium hydroxide solution is added into an alkaline hydrolysis reactor in advance, an amination liquid is collected from an amination liquid outlet, a reaction is undergone at the temperature of 60-90 DEG C under the pressure of between -0.01 MPa and -0.09 MPa, and ammonia in a system is recovered simultaneously. In the process, the tubular reactor is taken as an amination reactor, so that the reaction temperature and pressure are raised, the reaction time is shortened, and raw material decomposition, pyrolytic polymerization of aminoacetonitrile and the generation of byproducts are reduced; alkaline hydrolysis is performed during the collection of the amination liquid, the concentration of an alkaline liquor and the alkaline hydrolysis temperature are raised simultaneously, and ammonia in the system is recovered under reduced pressure, so that the alkaline hydrolysis reaction is more complete, the speed is higher, and the generation of colored impurities is reduced; and a mother liquor circular utilizing mode is established, so that the treatment amount of waste mother liquor is reduced, the product yield is increased, and the production cost is reduced.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a technique for preparing glycine with hydroxyacetonitrile and ammonia water as raw materials. Background technique [0002] Glycine is an important fine chemical product, which is widely used in medicine, food, chemical industry, pesticide and other fields. There are many preparation techniques for glycine. Chinese patent CN1962611B discloses a technique for preparing glycine by the hydroxyacetonitrile method, which includes the following steps: 1) mixing hydroxyacetonitrile and ammonia water, and the molar ratio of the reaction liquid is hydroxyacetonitrile:ammonia=1: 2~10, control the reaction temperature between 20~60°C, and the reaction time is 0.5~8 hours to obtain the ammonia solution of aminoacetonitrile; 2) Add inorganic alkali directly to the ammoniated solution obtained in step 1), and the reaction material The molar ratio is aminoacetonitrile:inorganic base=1:0.7~3.0...

Claims

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Application Information

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IPC IPC(8): C07C229/08C07C227/42C07C227/02
Inventor 王友仁秦岭李文艳刘丹李俊峰陈修毅朱丽利龙晓钦
Owner CHONGQING UNISPLENDOUR CHEM
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